[Kavelach]

As I mentioned above - one or two clauses like that won't hurt performance, but I have seen situations, when bad CSS (a lot of *'s, too long selectors, a lot of dead and unused clauses) actually had a measurable impact on websites' performance.

This especially comes into play, if you deal with a lot of nested HTML elements or when you modify the site's HTML a lot.

[the_other]

That sounds like a different problem from using the owl selector. That sounds like bad coding and app design.